A 52-year-old woman from Mumbai presents with a 2-week history of progressive hoarseness, difficulty swallowing, and weakness of the right shoulder. On examination, she has right vocal cord paralysis (confirmed on laryngoscopy), weakness of right sternocleidomastoid and trapezius muscles, and absent right gag reflex. Her tongue is midline. Imaging reveals a mass at the skull base near the jugular foramen. Which cranial nerve is NOT involved in this patient's presentation?